The best the U.S. and its NATO allies may be able to hope for is what he refers to as "Afghan good enough." That is, Cordesman said earlier on Morning Edition, an Afghanistan in which only parts of the country are protected by Afghan government forces and much of the rest of the nation remains vulnerable to the Taliban and extremists. It would be too expensive — in lives and money — to try to secure the whole nation, he says.

"A suicide car bomber and Taliban militants disguised in burqas attacked a compound housing hundreds of foreigners in the Afghan capital on Wednesday, killing seven people, officials and witnesses said. The Taliban said the attack was a response to President Barack Obama's surprise visit just hours earlier." (The Associated Press)

Some other day-after analyes about the president's trip and the agreement he signed with Afghan President Hamid Karzai about U.S.-Afghan relations after the withdrawal of most foreign forces in 2014:

-- "At its heart, [Obama's] speech was a balancing act. The vast majority of Americans want to get out of Afghanistan and end the war. But anything that looks like cutting and running, leaving the Afghans in the lurch, would be criticised by the foreign policy establishment and by some allies, as well as his obvious opponents." (BBC North America editor Mark Mardell)

President Obama left Afghanistan around dawn (local time) today, and his due back at the White House around midday.